Free Monte Carlo simulations of your downswings, bankroll needs, and long-run results – so you can tell variance apart from a real leak.
Your Parameters
Enter your assumed inputs below. We'll use these values for all calculations and simulations.
1 buy-in = 100 BB = $500.00
Winrate5 bb/100
-10 bb/10030 bb/100
Std Dev100 bb/100
50 bb/100200 bb/100
Sample Size50k
10k500k
Bankroll50 buy-ins
5 buy-ins100 buy-ins
Expected value · 50,000 hands
+$12.5k
+25.0 buy-ins
Profit probability86.8%
Risk of ruin0.7%
Very safe · 50 buy-in bankroll
Important: Moving down before losing most of your bankroll is highly recommended. Hence, this Risk of Ruin number doesn't mean actual busto. If you won't move down, a Risk of Ruin above 1% becomes very high!
Quick ranges
Best case (5%)+$30.9k
Likely range+$5.0k to +$20.0k
Worst case (5%)$-5.9k
Outcome Percentiles
Best 1%
+$38.5k
77.0 BI
Top 5%
+$30.9k
61.8 BI
Top 25%
+$20.0k
40.1 BI
Median
+$12.5k
25.0 BI
Bottom 25%
+$5.0k
9.9 BI
Bottom 10%
$-1.8k
-3.7 BI
Worst 1%
$-13.5k
-27.0 BI
Profit Probability Over Time
10k
69.1%
25k
78.5%
50k
86.8%
100k
94.3%
250k
99.4%
500k
>99%
Enter Your Current Downswing
≈ 20.0 BI (2000 BB)
Traditional Downswing Calculator (Net Result)
2.0%chance
Down ≥ 20.0 BI in 25,000 hands
Running ice cold
This is the probability of ending 25,000 hands at or below that result. (Not peak→trough drawdown risk.)
What if your true winrate is different?
+5 bb/100
2.0%
+2.5 bb/100
4.8%
0 bb/100
10.3%
-2.5 bb/100
19.2%
Heads Up
Traditional Downswing Math is Misleading
Those calculations show the odds of a downswing starting right now. But downswings can start anytime—so the lifetime odds are much higher.
What You Actually Need To Think About (Peak → Trough Risk)
Enter Your Volume
How many hands do you play per month?
—chance / year
Over 300,000 hands/year, chance of a max drawdown ≥ 20.0 BI (2000 BB) (≈ $10.0k)
Why does probability increase with more hands? This calculates the chance of experiencing this drawdown at some point during the period, not ending at that result. More hands = more opportunities for variance to create a large drawdown from your peak, even if you're expected to be up overall.
Estimated via — simulations (100-hand blocks)
Per Month
—
25,000 hands
Per Quarter
—
75,000 hands
Per Year
—
300,000 hands
Bankroll Requirements
5%
Risk
Style
Buy-ins
Amount
1%
Very conservative
47
$23.0k
2%
Conservative
40
$19.6k
5%
Standard
30
$15.0k
10%
Aggressive
24
$11.5k
Based on 5 bb/100 winrate, 100 standard deviation
Important: Moving down before losing most of your bankroll is highly recommended. Hence, this Risk of Ruin number doesn't mean actual busto. If you won't move down, a Risk of Ruin above 1% becomes very high!
Required Bankroll · 5% RoR
$15.0k
30 buy-ins
Your Current Bankroll
Amount$25.0k
Buy-ins50
StatusSufficient
Heads Up
What If You're Wrong?
Your bankroll calculations are only as good as your winrate estimate. If you're wrong about your edge, your risk of ruin changes dramatically.
Alternate Win Rates
Your Assumption
5.0bb/100
Bust Risk0.7%
Safe Bankroll30 BI
Slightly Worse
3.5bb/100
Bust Risk3%
Safe Bankroll43 BI
Much Worse
1.5bb/100
Bust Risk22%
Safe Bankroll100 BI
Breakeven
0bb/100
Bust Risk>99.9%
Safe Bankroll∞
*"Safe" bankroll = 5% risk of ruin. Only if you plan to move down!
Backing Arrangement
Understanding the Deal
In a backing arrangement, the backer provides the bankroll and absorbs all losses. Profits are split at regular intervals (chops). When losing, the player goes "in makeup" — they owe the backer that amount before they can take profit cuts again. The player can never lose money, only time.
Deal Parameters
Backer's Cut
50%
Hands / Session
Sessions / Chop
Backer's Risk of Ruin
0.1%
Very Low
Probability of losing entire $25.0k bankroll
Important: Moving down before losing most of your bankroll is highly recommended. Hence, this Risk of Ruin number doesn't mean actual busto. If you won't move down, a Risk of Ruin above 1% becomes very high!
Backer vs Player
Backer
Expected Value
+$5.2k
Profit Probability
80.6%
Median Outcome
+$5.6k
Player
Expected Value
+$7.2k
Profit Probability
93.6%
Median Outcome
+$6.9k
Total Hands
50,000
Hands / Chop
15,000
Number of Chops
3
Backer Bankroll
$25.0k
Makeup Statistics
Avg Makeup
$2.1k
In Makeup at End
49.5%
Deal Math (EV Split)
Total EV+$12.5k
Backer (+$5.2k)41%
Player (+$7.2k)59%
Note: The backer's true EV is lower than a naive 50/50 split because they absorb 100% of downswings but only receive 50% of profits.
Backer Distribution
-$26.0k$26.0k
LossProfitMean +$5.2kMedian +$5.6k
Player Distribution
$0$25.5k
LossProfitMean +$7.2kMedian +$6.9k
Based on 10,000 Monte Carlo simulations. The backer's distribution is asymmetric because they absorb all losses but only collect a portion of profits.
Enter Your Actual Results
Input your poker results to see if you are likely a winning player.
Credible Intervals for True Winrate
Observed: 8.0 BB/100
95%
-4.4 to 20.4
90%
-2.4 to 18.4
75%
0.7 to 15.3
60%
2.7 to 13.3
Dark gray line = your observed winrate. Green line = breakeven (0 bb/100). If an interval crosses zero, you can't be confident you're a winner at that confidence level.
Probability You're a Winner
89.7%
Probably a winner
Observed Stats
Winrate8.0 bb/100
Std Error±6.32 bb/100
95% Range-4.4 to 20.4
Hands Until You Know
How many hands to know your winrate within a given accuracy?
±bb/100
615k
hands needed (95% confidence)
When Can You Trust Your Results?
10k
±10.0 bb/100
30k
±5.8 bb/100
50k
±4.5 bb/100
100k
±3.2 bb/100
250k
±2.0 bb/100
500k
±1.4 bb/100
Bars show relative statistical confidence. Numbers show 95% CI margin for your winrate.
Year in Review
Simulating the Future
This came from a conversation with a BTG member who was struggling through a rough stretch. Being able to see what a year might look like — the swings, the variance — can help when you're in the middle of one of those months. Enter your volume below and use the Re-roll Year button to put things in perspective.
Enter Your Volume
Monthly Variance Breakdown
Annual Result+$43.2kactual P&L
Annual EV+$45.0kexpected value
Year Variance$-1.8kbelow EV
Lucky Months2>1 SD above EV
Unlucky Months3>1 SD below EV
LuckiestJanuary+2.0 SD
UnluckiestNovember-2.4 SD
Jan🍀
Actual+$13.7k
EV+$3.8k
Variance+2.0 SD
Feb
Actual+$4.9k
EV+$3.8k
Variance+0.2 SD
Mar
Actual+$3.6k
EV+$3.8k
Variance-0.0 SD
Apr
Actual+$2.8k
EV+$3.8k
Variance-0.2 SD
May🍀
Actual+$13.0k
EV+$3.8k
Variance+1.9 SD
Jun💀
Actual$-4.1k
EV+$3.8k
Variance-1.6 SD
Jul
Actual+$6.6k
EV+$3.8k
Variance+0.6 SD
Aug
Actual+$6.8k
EV+$3.8k
Variance+0.6 SD
Sep💀
Actual$-1.7k
EV+$3.8k
Variance-1.1 SD
Oct
Actual+$6.0k
EV+$3.8k
Variance+0.5 SD
Nov💀
Actual$-7.9k
EV+$3.8k
Variance-2.4 SD
Dec
Actual$-406
EV+$3.8k
Variance-0.8 SD
Five Year Simulation
The Long Game
This tab simulates 5 years of poker with automatic stake progression. Customize the rules below. Notice how a 25 buy-in downswing — which feels enormous in the moment — becomes a tiny blip on a 5-year graph.
Volume
·
50buy-ins↗
·
Stakes
BI?
BI?
·
% ×lvls, then%?
$5/bb
$10/bb
$20/bb
$50/bb
$100/bb
$200/bb
$400/bb
Starting Bankroll
$25,000
Final Bankroll
$1,170,522
Profit
+$1,145,522
25 BI at Starting Stakes
$12,500
Highest Stakes
$400/bb
Move-Ups
7
Move-Downs
1
Over 60,000 subscribers get insights, strategies, and ideas from Phil Galfond every week.
Poker Variance – FAQ
What is poker variance?
Variance is the gap between your expected results and your actual results over a given number of hands. Two players with the exact same win rate can have wildly different months – one runs hot, one runs cold. That gap is variance, and this tool lets you see its real shape instead of guessing at it.
How do I use this calculator?
Set your assumed win rate, standard deviation, sample size, and bankroll up top. Everything below – expected outcomes, downswings, bankroll requirements – recalculates instantly from those inputs. If you are not sure of your numbers, start with the defaults and adjust as you get to know your own game.
What does a normal downswing look like?
Bigger than most players think. Even a clear winner runs through stretches that feel like the floor dropped out. The Downswings tab simulates how deep and how often those swings happen at your win rate and standard deviation – so you can tell the difference between a normal cold run and an actual leak.
How big should my bankroll be?
It depends on your win rate, your standard deviation, and how much swing you can stomach – not on a one-size-fits-all number of buy-ins. The Bankroll tab shows your risk of going broke at different bankroll sizes, so you can pick a number you can actually sleep on.
Can this tell me if I am a winning player?
Not for certain – nobody can, over a small sample. But the "Am I a Winner?" tab shows the range of true win rates that are consistent with your results, and how confident you can reasonably be. The honest answer is almost always that you need more hands than you would like.
Are these results guaranteed?
No. These are statistical approximations based on the normal distribution – they show what is likely, not what will happen. Real poker has fatter tails than any clean model. Treat the output as a map, not a promise.